1918.] NATURAL SCIENCES OF PHILADELPHIA. 299 
24. Southern slope of mountains at eastern gate of John Rhodes’ ranch, among 
boulders on mesa. 
26. Rhodes’ canyon. 
27. Northern slope, amphitheatre on Whitlock ranch. 
28. Foot of main gulch facing north, same amphitheatre. 
29. Farther up same gulch. 
30. “Porphyry” slide on trail 1} miles south of Copper Creek Mining Camp. 
Type locality. 
31. Camp at smelter, Copper Creek. 
32. Rock slide sloping west, on trail half way between Copper Creek Camp and 
Table Mountain. 
33. “Porphyry” slide in forks of creek 2 miles east of Table Mountain. 
34. Slide near the preceding. 
35. Cliffs on northeastern slope of Table Mountain. 
Genitalia (fig.7). The general proportions are as in S. marmor- 
arius. The penis has a long, very thin sheath about the basal part, 
not seen in marmorarius; its lower portion is somewhat swollen and 
has several small longitudinal folds within. Retractor muscle long. 
Papilla weakly annulate, about half as long as the penis. There is 
the usual short flagellum. The vagina about equals the penis in 
length. 
Length of penis ........ 10 mm. 
papillac hee: Bre 
epiphallus....7 =“ 
flagellum ....1.5 “ 
sya 06: Mapa et 
Mriscuna NGl 2 2h... S224 118,122. 
This form is much like S. marmorarius. The shell is slightly more 
capacious and darker colored, and there is some difference in the penis. 
Its habitat is separated from that of marmorarius by the valley of 
the San Pedro River. The elevation is much less than that in- 
habited by S. marmorarvus. 
20 living specimens from Station 30, all taken, measure as fol- 
lows: 
Wiamieters in mama a: 251425:5". 26 26.5 -27 27.5 28: 29 
Nosepecimens «<0. ().)@)---@)-- @) 3). @) ».@) @) 
17 specimens from Station 24, a southern slope: 
Diameters....... DA 24 De 26 26.5 -27- 28) 28.6308 
No. specimens....(1) (2) (3), (2) tA) oC Gy) (1) 
Sonorella tortillita n. sp. Pl. V, figs. 4, 4a, 4b. $s 
The shell is umbilicate (width of umbilicus contained about 83 
times in that of the shell), pinkish buff, fading to white around the 
umbilicus and paler near the chestnut-brown band which revolves 
above the periphery of the last whorl and shows very narrowly above 
the suture on most of the penult whorl. The surface is glossy; 
